Osama bin Laden was named in an FBI memorandum written two months before September 11 warning that his followers could be training for terrorist missions at American flight schools, it was reported yesterday. News also emerged of plans for a counter-terrorist "supersquad" to stop such tip-offs being ignored.

The "Phoenix memo"- sent by an agent in the Arizonan capital last July, urging a nationwide investigation of Middle Eastern men at flight schools - came to light several weeks ago. The al-Qaida chief was specifically implicated.

The men being investigated at the schools are not thought to have been involved in the September 11 attacks, but members of Congress who have seen the document say it is the most damning evidence yet that a better-run FBI might have been able to gain advance intelligence on the attack.

Just as extraordinary is the Newsweek claim that Zacarias Moussaoui, the French citizen on trial for allegedly conspiring with Bin Laden, had been named in another agent's notes, in August, which said that he might try to fly a plane into the World Trade Centre.

The FBI supersquad would involve hiring 1,600-plus employees and analysts fluent in Middle Eastern languages over the next 18 months to bolster the 4,100 staff already assigned to counter-terrorism.

"It is really kind of anachronistic to believe that we should be handling terrorism cases the same way we handle narcotics or public corruption," a senior US official told the Washington Post.